Influence of heart surgery on magnesium concentrations in pediatric patients

Intravenous magnesium as acute treatment for headaches: a pediatric case series

BACKGROUND

Acute i.v. treatment for pediatric headache varies widely.

OBJECTIVES

Our aim was to describe our experience with i.v. magnesium for acute treatment of pediatric headache.

METHODS

We reviewed the electronic medical records of all patients ages 5 to 18 years old treated with a standard dose of i.v. magnesium for headache at our institution from January 2008 to July 2010. Charts were assessed for headache diagnosis, prior medications given, side effects, tolerability, and response to treatment. Individuals were excluded if they had an underlying unstable medical condition or a secondary etiology for headache. Only first encounters were included if the patient had multiple encounters.

RESULTS

There were 34 episodes of children who received i.v. magnesium in the emergency department (ED) or hospital. Of these, 14 were excluded because the patients had complex medical conditions (n = 6), they were repeat encounters (n = 7), or known secondary etiology for the headache (n = 1). Of the 20 included charts (range 13-18 years old), 5 had migraine, 4 had tension-type headache, and 11 had status migrainosus. Thirteen were treated in the ED and seven as an inpatient with a standard i.v. dose of magnesium. Ten of thirteen adolescents receiving i.v. magnesium in the ED were admitted for further headache treatment but not for side effects, and three were discharged home. Side effects of treatment included pain (1 of 20), redness (1 of 20), burning (1 of 20), and decreased respiratory rate without change in oxygenation (1 of 20).

CONCLUSIONS

In our case series, adolescents given i.v. magnesium as an abortive therapy for headache experienced minimal side effects and further studies should evaluate for effectiveness.

Magnesium supplementation reduces postoperative arrhythmias after cardiopulmonary bypass in pediatrics: a metaanalysis of randomized controlled trials

Postoperative arrhythmia (POA) is the most common complication encountered after cardiopulmonary bypass (CPB). The preventive effect of magnesium in POA has been confirmed by metaanalyses in adults, but less is known in pediatric patients. A metaanalysis of published trials was conducted to examine the efficacy of magnesium supplementation in POA prevention among pediatric patients undergoing CPB. Relevant trials were identified from electronic databases (Medline, Embase, Web of Science, and Cochrane library). Pooled relative risk (RR) and 95 % confidence intervals (CI) were calculated using Mantel-Haenszel random-effects models, and heterogeneity was determined qualitatively according to I (2) and chi-squared statistical analyses. Among 121 potentially relevant studies, five randomized controlled trials met the inclusion criteria, resulting in a pooled total of 348 participants. Compared with placebo, magnesium supplementation decreased the incidence of arrhythmia after CPB in pediatric patients by 66 % (RR, 0.34; 95 % CI, 0.18-0.65; P = 0.001), with no heterogeneity between trials (heterogeneity P = 0.68; I (2) = 0 %). Magnesium supplementation significantly reduces the incidence of postoperative arrhythmias in pediatric patients undergoing CPB. Although the findings encourage the use of magnesium as an alternative to postoperative arrhythmias after CPB in pediatric patients, higher-quality randomized clinical trials are necessary before the findings can be generalized.

The roles of antimicrobial peptides in innate host defense

Antimicrobial peptides (AMPs) are multi-functional peptides whose fundamental biological role in vivo has been proposed to be the elimination of pathogenic microorganisms, including Gram-positive and -negative bacteria, fungi, and viruses. Genes encoding these peptides are expressed in a variety of cells in the host, including circulating phagocytic cells and mucosal epithelial cells, demonstrating a wide range of utility in the innate immune system. Expression of these genes is tightly regulated; they are induced by pathogens and cytokines as part of the host defense response, and they can be suppressed by bacterial virulence factors and environmental factors which can lead to increased susceptibility to infection. New research has also cast light on alternative functionalities, including immunomodulatory activities, which are related to their unique structural characteristics. These peptides represent not only an important component of innate host defense against microbial colonization and a link between innate and adaptive immunity, but also form a foundation for the development of new therapeutic agents.

Immunomodulatory properties of defensins and cathelicidins

Host defence peptides are a conserved component of the innate immune response in all complex life forms. In humans, the major classes of host defence peptides include the α- and β-defensins and the cathelicidin, hCAP-18/LL-37. These peptides are expressed in the granules of neutrophils and by a wide variety of tissue types. They have many roles in the immune response including both indirect and direct antimicrobial activity, the ability to act as chemokines as well as induce chemokine production leading to recruitment of leukocytes to the site of infection, the promotion of wound healing and an ability to modulate adaptive immunity. It appears that many of these properties are mediated though direct interaction of peptides with the cells of the innate immune response including monocytes, dendritic cells, T cells and epithelial cells. The importance of these peptides in immune responses has been demonstrated since animals defective in the expression of certain host defence peptides showgreater susceptibility to bacterial infections. In the very few instances in which human patients have been demonstrated to have defective host defence peptide expression, these individuals suffer from frequent infections. Although studies of the immunomodulatory properties of these peptides are in their infancy, there is a growing body of evidence suggesting that the immunomodulatory properties of these small, naturally occurring molecules might be harnessed for development as novel therapeutic agents.

Impact of LL-37 on anti-infective immunity

Host defense peptides (often called cationic antimicrobial peptides) have pleiotropic immunomodulatory functions. The human host defense peptide LL-37 is up-regulated at sites of infection and has little or no antimicrobial activity in tissue-culture media but under the same conditions, demonstrates immunomodulatory effects on epithelial cells, monocytes, and dendritic cells (DC). These effects include the induction of chemokine production in a mitogen-activated protein kinase-dependent manner in epithelial cell lines and monocytes and profound alterations of DC differentiation, resulting in the capacity to enhance a T helper cell type 1 response. Although the exact mechanisms of interaction between LL-37 and these cell types have not been elucidated, there is evidence for specific (i.e., receptor-mediated) and nonspecific interactions. The relative significance of the direct antimicrobial activities and immunomodulatory properties of LL-37 and other cationic host defense peptides in host defense remains unresolved. To demonstrate that antimicrobial activity was not necessarily required for protection in vivo, model peptides were synthesized and tested for antimicrobial and immunomodulatory activities. A peptide with no antimicrobial activity was found to be protective in animal models of Staphylococcus aureus and Salmonella infection, implying that a host defense peptide can protect by exerting immunomodulatory properties.